J/A+A/625/A13 Outburst of V1318 Cyg S (LkHa 225) (Magakian+, 2019)
New powerful outburst of the unusual young star V1318 Cyg S (LkHa 225).
Magakian T.Yu., Movsessian T.A., Andreasyan H.R., Gevorgyan M.H.
<Astron. Astrophys. 625, A13 (2019)>
=2019A&A...625A..13M 2019A&A...625A..13M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence; Stars, variable ; Spectroscopy
Keywords: stars: pre-main sequence - stars: variables: T Tauri, Herbig Ae/Be -
stars: individual: V1318 Cyg S
Abstract:
Young double star V1318 Cyg, which is associated with a small isolated
star-forming region around HAeBe star BD+40 4124, has very unusual
photometric and spectral behavior. We present results of photometric
and spectroscopic observations in the optical range.
We carried out BVRI CCD photometric observations of V1318 Cyg from
2015 Sept. to 2017 July. For the same period we acquired medium- and
low-resolution spectra. Observations were performed with the 2.6 m
telescope of the Byurakan observatory. We also analyzed the images of
this field in IPHAS and other surveys.
We analyze the historical light curve for V1318 Cyg and demonstrate
that the southern component, V1318 Cyg S, after being rather bright in
the 1970s (V∼14 mag) started to lower its brightness and in 1990
became practically invisible in the optical. After its reappearance in
the second half of the 1990s the star started to become very slowly
brighter. Between 2006 and 2010 V1318 Cyg S started brightening more
quickly, and in 2015 had become brighter by more than five magnitudes
in visible light. Since this time V1318 Cyg S has remained at this
maximum. Its spectrum shows little variability and consists of a
mixture of emission and absorption lines, which has allowed for
estimates of its spectral type as early Ae, with obvious evidence of
matter outflow. We derive its current A(V)∼7.2 and L=750L(sun)
thus confirming that V1318 Cyg S should belong to the Herbig Ae stars,
making it, along with BD+40 4124 and V1686 Cyg, the third luminous
young star in the group. It is very probable that we observe V1318 Cyg
S near the pole and that the inclination of its dense and slow
(<100km/s) outflow is low.
The unusual variability and other features of V1318 Cyg S make it
difficult to classify this star among known types of eruptive young
stars. It could be an extreme, higher-mass example of an EXor, or an
object of intermediate class between EXors and FUors, like V1647 Ori.
Description:
Fourteen reduced spectra of V1318 Cyg S obtained in 2015-2016 with
various resolutions and ranges, normalized to continuum (format of
names: norddmm_yy). Four of them also are presented in relative
intensities in arbitrary units of the flux (format of names:
intddmm_yy). More details are given in the observational log in
Table 1 of the paper.
Objects:
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RA (2000) DE Designation(s)
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20 20 30.59 +41 21 26.3 V1318 Cyg S = LKHa 225 S
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 131 18 List of fits spectra
fits/* . 18 Individual spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 34 A10 "date" Obs.date Observation date
36- 39 I4 0.1nm blambda Lower value of wavelength interval
41- 47 F7.2 0.1nm Blambda Upper value of wavelength interval
49- 52 F4.2 0.1nm dlambda Spectral resolution
54- 55 I2 Kibyte size Size of FITS file
57- 72 A16 --- FileName Name of FITS file, in subdirectory fits
74-131 A58 --- Title Title of the FITS file
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Acknowledgements:
Tigran Magakian, tigmag(at)sci.am
(End) Tigran Magakian [BAO, Armenia], Patricia Vannier [CDS] 12-Apr-2019